<html xmlns:th="http://www.thymeleaf.org">
<head>
  <meta charset="UTF-8">
  <title>添加用户</title>
  <style>
    body {
      font-family: Arial, sans-serif;
      background-color: #f4f4f4;
      padding: 20px;
    }
    form {
      background-color: #fff;
      max-width: 300px;
      margin: 0 auto;
      padding: 20px;
      box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    }
    input[type="text"] {
      width: 100%;
      padding: 10px;
      margin-bottom: 10px;
      border: 1px solid #ddd;
      box-sizing: border-box;
    }
    input[type="submit"] {
      width: 100%;
      padding: 10px;
      background-color: #5cb85c;
      color: white;
      border: none;
      cursor: pointer;
    }
    input[type="submit"]:hover {
      background-color: #4cae4c;
    }
  </style>
</head>
<body>

<form th:action="@{/update}" method="post">
  <input type="hidden" th:field="${user.id}">
  <label for="username">用户名：</label>
  <input type="text" id="username" name="username" th:field="${user.username}"><br>
  <label for="age">年龄：</label>
  <input type="text" id="age" name="age" th:field="${user.age}"><br>
  <label for="address">地址：</label>
  <input type="text" id="address" name="address" th:field="${user.address}"><br>

  <input type="submit" value="修改">
</form>

</body>
</html>